Note: I am accessing roundcude via the LAN IP of the server rather than the FQDN as I am to lazy to adjust the firewall to test the FQDN, but it is working on our current production server which iRedMail will eventually replace.

I have also created an /etc/hostname file with the FQDN of the host and I have checked the /etc/host file to ensure it has the correct host name and domain.